However, the study may suggest that advances in technology can offer a richer understanding of wonders of the ancient world that have long fascinated the human imagination.
Khufu, also known by his Greek name Cheops, is thought to have ruled from 2509 B.C. to 2483 B.C., during Egyptâs fourth dynasty. Though he constructed the largest pyramid Egypt has ever seen, the only intact three-dimensional figure of him that archaeologists have found measures a mere three inches tall. Very little is known about him, so his pyramid offers one of the few looks into his life and reign. The site at Giza where his pyramid was built also contains two other major pyramids and the Sphinx.
Since 2015, Dr. Tayoubi and his colleagues, now consisting of three separate teams of physicists and engineers, have investigated the pyramid using a particle physics technique known as muon-tomography to see through to its core.
âWe tried to do for the pyramid what a doctor can do with X-rays,â Dr. Tayoubi said.
Instead of X-rays, the team used muons, the heavy cousins of electrons that form when cosmic rays from outer space collide with particles in Earthâs atmosphere. The fallout from the collisions creates a constant bombardment of harmless particles that can penetrate deep into the planet. As the muons pass through matter they lose energy and decay, so if the team detected a small amount of muons, that means they were passing through matter. But if they detected more muons, it suggests the particles were passing through empty space or less dense material.
The technology was previously used by Luis Alvarez, a Nobel Prize winning physicist, to investigate whether there were hidden chambers in the Pyramid of Khafre in the 1960s. As muon detector resolution has greatly improved over the decades, it has since been used to see the inner structures of volcanos as well as the irradiated Fukushima nuclear reactor.
In 2016, Dr. Tayoubiâs colleagues stood in the Queenâs chamber and used muon detectors capable of making improved measurements to study particles as they passed through the pyramid. When they analyzed their data from a region above the Grand Gallery, a long inclined passageway that leads to the Kingâs Chamber, they found something strange: an unexpected excess of muons.
They found a void.
The first measurements were made by researchers from Nagoya University in Japan who were a part of the project. Then two more teams associated with ScanPyramids, one from France and another from Japan, also confirmed the anomaly with muon tomography, even from outside the pyramid. The discovery comes on the footsteps of the teamâs previous work which detected a small void behind the north face of the pyramid in 2016.
Christopher Morris, a physicist who conducts research using muon tomography at Los Alamos National Laboratory and was not involved in the study, called the findings âpretty amazing,â adding that all the team needed to do was set up their muon detectors and reap the rewards.
âAll the other physicists who could have done it, and didnât, are jealous,â he said.
Arturo Menchaca-Rocha a physicist from the National Autonomous University of Mexico who has used muon detection to investigate the Pyramid of the Sun in Mexico, echoed Dr. Morrisâs sentiments and said the projectâs physics supported its claims.
But archaeologists were more critical of the work.
Mark Lehner, an Egyptologist from the Ancient Egypt Research Associates, said that previous work had shown that the ancient Egyptians most likely constructed gaps in their pyramids and that the voids the team found are nothing special, or new.
âThe great pyramid of Khufu is more Swiss cheese than cheddar,â he said. He added that the steep incline of the void also casts doubts on whether it was some sort of room. âAt that angle, it doesnât make much sense for it to be a chamber that would contain artifacts, burials and objects and that sort of thing.â
Zahi Hawass, an Egyptologist, former Egyptian government minister and head of the scientific committee appointed by the Egyptian Ministry of Antiquities to review the work, was more critical of the finding.
âThey found nothing,â said Dr. Hawass, noting that such construction gaps had been known of for at least two decades. âThis paper offers nothing to Egyptology. Zero.â
Both Dr. Lehner and Dr. Hawass agreed that the scanning work should continue in hopes that the teams can retrieve higher resolution data about the inner workings of the pyramid, specifically the shape and size of the anomaly.
Hany Helal, who is also co-director of the ScanPyramids project, responded to the criticism saying that from an engineering perspective, it would not make sense to have such a big void above the Gallery if its purpose was to relieve pressure.
He said the next steps are to have an international discussion with archaeologists to figure out the structureâs purpose. In the future, he added that scientists may use drones to explore the void once they have more information about it.
âWe are sure there is a void,â he said. âNow let us continue our research.â